A numerical method for spatially-distributed transient simulation to replicate nonlinear 'defect-irrelevant' behaviors of no-insulation HTS coil

Abstract

This paper presents a numerical method, based on the partial element equivalent circuit (PEEC) technique, for spatially-distributed and time-varying simulation to analyze nonlinear 'defect-irrelevant' behaviors of a no-insulation (NI) high temperature superconductor (HTS) coil. We suggest a resistivity parameterization approach in combination of the PEEC method to replicate electromagnetic dynamics of an NI HTS coil containing multiple 'defects.' The proposed method is adopted to investigate 'defect-irrelevant' behaviors of an NI single pancake coil having lap joints as a form of artificial defects. To validate our approach, electromagnetic characteristics of the NI test coil are measured in a bath of liquid nitrogen at 77 K and compared with four key simulation results: (a) local voltages; (b) current distribution; (c) magnetic field; and (d) Joule heating distribution. Experimental measurements of local voltages and the magnetic field are compared to the simulation results to validate our numerical method.